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S. H. AYERS, C. S. MUDGE AND PHILIP E.UPP 



After the agar is washed, it may be air dried, and then used 

 the same as ordinary agar. It is only necessary to use 1 per 

 cent of the dry material to obtain a medium having the same 

 jelly strength as a 1.5 per cent shred agar medium. 



Various methods were tried for washing shred agar, and the 

 effect of these treatments on the calcium and magnesium content 

 will be of interest. As shown in table 2, ordinary shred agar 

 contained about 16 per cent of moisture. On an air-dry basis 



TABLE 2 

 Analyses of various kinds of agar 



the per cent of ash was about 4.4. The calcium content was 

 about 1.15 per cent, calculated as CaO, and the magnesium 

 about 0.77 per cent, calculated as MgO. 



Two lots of commercially purified agar were examined. These 

 were purchased at different times, and probably do not represent 

 one orginal lot of the material. The agar was said to contain 

 a minimum amount of moisture, when packed, and to have been 

 specially treated to reduce the extraneous matter, inorganic 



